1. Technical Field
The present disclosure relates to methods for determining response characteristics of a battery.
2. Related Art
One of methods for determining response characteristics of a battery is an impedance determination. In the impedance determination, an alternating voltage or an alternating current is applied to a battery to obtain current response or voltage response from the battery. Results of the impedance determination can be represented as, for example, a Nyquist plot.
Results of impedance determination vary depending on a history of battery state prior to starting of the impedance determination. Prior to the determination, for example, the voltage of a subject battery (hereinafter, referred to as a subject battery) is adjusted from initial voltage V0 to arbitrary set voltage Vs. The adjustment is made by charging or discharging the battery. The impedance determination is started, for example, immediately after completion of the voltage adjustment. Alternatively, the impedance determination may be started after a specific rest time since completion of the voltage adjustment. In the latter case, the rest time is not always fixed at a given period of time. An experimenter can arbitrarily determine the rest time. For example, “Kinetic Characterization of Single Particles of LiCoO2 by AC Impedance and Potential Step Methods”, K. Dokko et al., Journal of The Electrochemical Society, vol. 148, (5), A422-426 (2001) describes an example of setting a rest time prior to starting of impedance determination.